98 4.0L that constantly runs horrible anf gets horrible gas mileage... the check engine light is on and when I check the code it says "system to lean" "bank 1" "bank 2" "cylinder four not firing"....I have replaced the oxygen sensors, all 3, replaced the MAS and spark plugs/wires... but the problem persist...what is going on?

 

did u gap the plugs right? and running a can of sea foam why not.

i'm sure someone will know of some other things to try

 

I have my own theory on this... and did a google search on this, as I have been having a similar problem and had those codes a while back...

I have also heard of a fuel pump that has/is going bad causing this problem.... might be worth checking into... I'm gonna try it later next week after I get moved into my new house... If you get to it before I do, lemme know how it goes.

 

fuel filter? fuel injectors?

run some fuel cleaner through it.

check spark plug gap and check to make sure the spark plug wires are connected well

 

I was getting this code when I had a bad maf,system to lean" "bank 1" "bank 2. Went to the junkyard got 1 and it went away . Was the 1 u got new.

 

Unplug the MAF and trying driving it. The PCM will go to a default setting.. but if that's the problem it ought to run better.

Rich

 

thank you all. the MAS was new; however I am going to start with the fuel pump and then get a fuel injector cleaning done. I am curious about the sea foam and will look into it. again thanks...Rangers Rule!

 

I am sorry for whoring the thread but every time I read the title I think of alcohol! That is all